Nonaqueous Sol-Gel Synthesis of Anatase Nanoparticles and Their Electrophoretic Deposition in Porous Alumina

Titanium dioxide (TiO2) nanoparticles were synthesized by nonaqueous solgel route using titanium tetrachloride and benzyl alcohol as the solvent. The obtained 4 nm-sized anatase nanocrystals were readily dispersible in various polar solvents allowing for simple preparation of colloidal dispersions in water, isopropyl alcohol, dimethyl sulfoxide, and ethanol. Results showed that dispersed nanoparticles have acidic properties and exhibit positive zeta-potential which is suitable for their deposition by cathodic electrophoresis. Aluminum substrates were anodized in phosphoric acid in order to produce porous anodic oxide layers with pores ranging from 160 to 320 nm. The resulting nanopores were then filled with TiO2 nanoparticles by electrophoretic deposition. The influence of the solvent, the electric field, and the morphological characteristics of the alumina layer (i.e., barrier layer and porosity) were studied.